Process for treatment of hydrocarbons



mmh 25% 11939, w, A SCHULZE PROCSS FOR TREATMENT OF HYDROCARBONS FiledMay 16, 1955 m a wacom NIW ONA tl A @XM vm mJ ii mmzsoasu @353m m. A.118@1 2.650.551 1.15.1 X11 1l oEmo Vzw Q 00mm mommw MNT WWI A111109 2m. L

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Patented Mar. 28, 1939 vk'UNITED STATES PATENT OFFICE vPROCESS FORTREATMENT 0F HYDRO- CARBONS Walter A. Schulze, Bartlesville, Okla.,assignor to vPhillips Petroleum Company, Bartlesville,

Okla., a corporation of Delaware Application May 16, 1935, Serial No.21,903 3 Claims. (Cl. ISG-27) This invention relates to a process oftreating hydrocarbons. and relates particularly to desulfurization ofhydrocarbon oils, particularly petroleum, shale oil and other mineraloils, and vmore particularly their products. y

An object of this invention is to provide a method forstreatinghydrocarbon oil containing` undesirable sulfur compounds comprising aseries of desulfurization steps designed to greatly reduce'the sulfurcontent of the hydrocarbon oil.

A principal object of this invention is to provide an improved methodfor desulfurization of hydrocarbon oil comprising a series ofdesulfurization steps in which each step is designed to remove aparticular type or group of sulfur compounds.

There are various types of sulfur compounds present in the mixtures ofhydrocarbons comprising petroleum, coal tar, shale oil and the like.These types of sulfur compounds maybe generally classified as (1) thealiphatic and aromatic mercaptans, suldes and disulfldes, which for thesake of brevity are termed non-heterocyclic sulfurcompounds, and (2)heterocyclc sulfur compounds, such as thiophenes and thiophanes. Carbondisulfide can hardly be placed in either group since it more -or lessfalls in between the two classes.

I have found that a more complete removal of sulfur from hydrocarbonmixtures containing these various classes of compounds can be obtainedby applying a diierent method of treatment to each of these generalclasses, rather than to attempt to remove or decompose all of theclasses with a single treatment. In other words, a series of treatmentseach designed to remove a particular group of sulfurcompounds from theoil is much preferred to a single treatment as heretofore proposed.

The aliphatic and'aromatic mercaptans,V sulfldes and disulfides may beremoved from hydrocarbon mixtures by decomposition of these sulfurcompounds to hydrogen suliide and the corresponding olenic-hydrocarbonsunder conditions such that there is no substantial ,decomposition of thehydrocarbon constituents of the mixture as described in co-pendingapplication, Serial No. 632,608, filed September 10, 1932, of A. E.Buell vand W. A. Schulze entitled fCatalytic process fordesulphurization of petroleum vapors. Carbon disulde, also, is partiallyremoved by such treatment.

The heterocyclic or thiophene type of sulfur compounds is notsdbstantially aiected under the conditions applicable to the compoundswherein moval of such sulfur.

the sulfur is not in the ring and a more rigorous treatment which mayeffect a partial decomposition of hydrocarbon constituents of themixture is required in this next step.

It has been'found that in effecting decomposi- 5 tion ofthe'heterocyclic type of sulfur compound the presence of appreciablequantities of hydrogen sulfide or other sulfur compounds greatly retardsthe decomposition of the heterocyclic sulfur compounds and, therefore,prevents the re- It is, therefore, particularlyadvantageous to iirsttreat the hydrocarbon mixture so as to decompose the aliphatic andaromatic mercaptans, sulfides and disuldes and then remove the hydrogensulfide from the hydrocarbons before treating for the removal'of' theheterocyclic sulfur. The method I have found best for decomposing thealiphatic and aromatic mercaptans, sulldes and disuldes in a hydrocarbonmixture to hydrogen sulfide comprises passing the mixture in the vaporphase at temperatures above 600". F. over a contact catalyst of the claytype, such as bauxite or fullers earth or the like, or some othercatalyst such as the oxides of chromium, vanadium, molybdenum,tungsten,. cadmium and zinc. The preferred temperature range for thisstep is generally between 600 F, and 800 F. with a treating time factorsufficiently short to avoid substantial decomposition of the hydrocarbonconstituents of the mixture. The hydrogen sulde formed may then beremoved from the treated vapors in a conventional mannergsuch as byfractionation or by washing with water, alkali, or other chemicalreagent general1y 'used for this purpose. This removal may be doneWithout appreciable cooling of the vapors, if desired, by absorption ofthe hydrogen sulfide in active oxide absorbents.

In my process these heterocyclic sulfur com- 40 pounds after removal ofthe other sulfur may be decomposed in either of two Ways.y Firstly, theymay be decomposed in the absence of catalysts by subjecting thehydrocarbon mixture containing them to temperatures at which thereisalso appreciable decomposition of the hydrocarbon constituents of-themixture. The temperature range is generally above 750 F. and may be ashigh as 1100D F. depending upon the time factor used and the type ofhydrocarbons being treated. This thermal decomposition may be conductedin'- any conventional apparatus suitable for thermally convertinghydrocarbons and it may be treated in the vapor phase, the liquid phaseor in the vapor-liquid phase, all such processes being absence ofcatalysts. and

hydrocarbon constituents. This treatment may be conducted in anypreferably is done in the vapor phase, although in certain instancesliquid phase o r vapor-liquid phase treatment may be desirable.

It has been noted that in the decomposition of the heterocyclic sulfureither of the above described methods most of the sulfur is converted tohydrogen sulfide',A although in some instances a part kof it may beconverted to aliphatic and aromatic mercaptans, suli'ldes; disulndes,etc. V,In cases where this organic sulfur is present in appreciablequantities the vapors may again be treated by the method described inthe first step, i. Le. passage in the vapor phase at temperatures abovel600 F'. over a contact catalyst of the clay type, such as bauxite orfullers earth or the like, whereby these organic sulfur compounds areconverted to hydrogen sulfide and the latter then removed in anyconventional manner.

In a preierredv embodiment, therefore, my invention contemplates thetreatment of hydrocarbons containing these various types of sulfurcompounds by (1) decomposing the aliphatic and aromatic mercaptans.alkyl sulndes and disulfldes, (2) removing the hydrogen sulfide from thetreated hydrocarbon mixture, -(3) decomposing the heterocyclic sulfurcompounds. and (4) removing the hydrogen sulfide from the treatedhydrocarbons. appreciable amount of sulfur in the form of aliphatic andaromatic mercaptans, sulfides or disulndes. then the lwdrocarbon mixture'is subjected (prior to step 4) to'another treatment as in step (l) todecompose'such compounds to hydrogen sulfide.

In 'the drawing accompanying this application there is showndiagrammatically, one form of apparatus for carrying out my invention.

Hydrocarbons are passed through the conduit I0 to an apparatus Ilfor'decomposition of nonheterocyclic sulfur compounds -under theconditions outlined above. 'Ihe emuents from this decomposition step arepassed through the conduit I2 to the separator Il, wherein hydrogensulilde formed as a result of the decomposition is separated from theeiiluents which are then passed by means of the conduit position step inapparatus Jl. wherein heterocyclic sulfur compounds forth more fullyabove. composition step are passed to a second separator l0 whereinhydrogen suliide is separated from the product which is removed by meansof conduit I1. In those instances where it is found desirable toseparate the lighter hydrocarbons from the heavier hydrocarbons prior todecomposition of the.

heterocyclic sulfur compounds, the eiiluents from the apparatus II mayIl by mea-ns of valves be diverted to a separator Il and 2l. SeparatorIl of treatment is lower than'- may be accomplished, ifv

to a'second apparatus desired, without substantial decomposition oi' they v case valve 26 could be conventional apparatus and' compoundsaccording to4 from the fractions containing If in step (3) there resultsan Il to'a second decomare decomposed as set` Emuents from the demay bein the form of a fractionator, cr other conventional apparatus capableof separating hydrogen sulfide, lighter hydrocarbons and heavierhydrocarbons. Hydrogen sulfide and lighter hydrocarbons are withdrawnthrough conduits 2| and 22.l respectively, and the heavier hydrocarbonsare passed by means of conduit 23 to a second decomposition apparatus I5for decomposition of heterocyclic sulfur compounds. Valves 2l and 2l maybe employed to effect proper flow. As previously stated, it is sometimesdesirable tointroduce the eiiiuents from the apparatus I5 for furtherdecomposition of non-heterocyclic sulfur compounds in which closed andvalve 2' opened from the apparatus I5 to the apparatus 2l whereindecomposition of any non-heterocyclic compounds formed in the apparatusIl under the conditions previously set forth may be accomplished.

Emuents from the apparatus 28 are then passed through the conduit 2l andvalve 30 to the separator I6, wherein hydrogen sulfide is removedproduct. Valve 3| will, oi' course, be

to divert the eilluents diagrammatically one be employed, it will theart that various the eifectuation of my invention.

My invention will be clearly understood from the following speciiicexamples of its application. A hydrocarbon oil such as mixture ofpetroleum sulfur compounds of both the general classes vgiven above isvaporized and heated to a temperature of 725 F. and the vapors tainedsubstantially at that temperature. vapors will be passed through thebauxite at a rate of approximately ten barrels (liquid volume) per hour.The non-heterocyclic sulfur in the form of aliphatic and aromaticmercaptans, suliides and disulildes is decompounds. The hydrogen sulfidewill then be removed from the mixture by one of the conventional methodsand a nal hydrocarbon mixture 40 y passed through a `bed of crushedbauxite maindisipar having a very-low sulfur content will the iinal,cent or a reduction of produce of the process.' v

By theabove described processa petroleum oil havingan original sulfurcontent oi' 0.20 per cent will show a final sulfur content oi' under0.05 per more thanl per cent in the original sulfur content.

It is also found; in lmany cases, that the maior portion of the sulfurin the form of aliphatic andl aromatic mercapt'ans, suliides 'anddisulildes will be concentrated in the lighter portions of a hydrocarbonmixture as, for example,`in the gaso.

line and naphtha fractions of a petroleum crude oil. In such cases,after the initial desuliurizavtion step of passing the total mixtureover bauxite or other catalyst mentioned above. itwill be foundeconomical and expedient to separate the gasoline and naphtha fractionsfrom the heavier fracfore desire sulfur compounds as `vwithin the rangefrom.

tions whichiare usually found to contain the principal portions of theheterocyclic type sulfur compounds, and to then subject only the heavierfrac- "tions to `the lsubsequent steps. Following the decomposition ofthe heterocyclic sulfur compounds contained therein, necessary, 4befurther desulfurized by the catalytic desulfurization step abovedescribed. i

Gther variations of'my invention will be readily apparent to thoseskilled in the art and I thereto claim all such variations which comewithin the scope of my new invention as de yuned bythe appended claims.By the term .nxr compounds are converted `into hydrogen sul- .nde butwithout any substantial conversion of the heterocyclic sulfur compoundsand the hydrocarbon constitutents of the vapors,

thevheavier fractions may; if

l non-heterocyclic` vsulfur as in the' appended claims I referparticularly to such the aliphatic and aromatic O v e 3 and removing theresultant hydrogen sulfide from the hydrocarbons. subjecting thehydrogen sulnde-freehydrocarbons to thermal treatment at a temperaturewithin the range of 800 to 1100' l". to decompose the heterocyclicsulfur compounds in-said hydrocarbons to hydrogen sulfide, and nallyremoving the said hydrogen sulfide from the treated hydrocarbons.

2. An improved method of desulfurizing light petroleum oil which containnon-heterocyclic and heterocyclic organic sulfur compounds, compris'-ing vaporizing saidpetroleum oil, contacting the said vapors while at atemperature within the range from 600 to 800" F. with a catalyst of theclay type for a period of abouti! to 10V seconds, whereby thelnon-heterocyclic organic sulfur compounds are converted into hydrogensulfide but without any substantial conversion of the heterocyclicsulfur compounds and the hydrocarbon constituents of the vapors,separating andremoving the resultant hydrogen sulfide from the`petroleum oil, subjecting the hydrogen suldefree petroleum oil tothermal treatment at a temperature within the range o! 800 to 1l00 F. todecompose the heterocyclic sulfur compounds in said petroleum oil tohydrogen sulfide. and finally removing the said hydrogen lsulfide fromthe treated oil. l f

3. An, improved method of desulfurizing light hydrocarbons which containnon-heterocyclic and heterocyclic organic sulfur compounds, comprisingvaporizing V,the said hydrocarbons,con tacting thesaid vapors while at atemperature within the range from 600 to.800 F. with a' desu'lfurizationcatalyst of the clay type for a period'v oi about 2 to l0 seconds,whereby the non-heterocyclic organic sulfur compounds are converted intohydrogen suliide but without any substan- -tial conversion oi' theheterocyclic sulfur compounds and the hydrocarboni constituents of the'vapors, separating and removing the resultant hydrogen sulnde from thehydrocarbons, contacting the hydrogen sulfide-free hydrocarbons with adesulfurization catalyst of the metallic oxide t l type at areactionvtemperature. whereby the heterocyclic sulfur compounds aredecomposed without any substantial decomposition of the hy- Y drocarbonconstituents. and iinally removing the saidl decomposed sulfurcompounds` from the treated hydrocarbons.

WALTER Alm. j

